This invention relates to improvements in or relating to apparatus for cleaning submerged surfaces. More particularly the invention relates to apparatus that automatically displaces itself across horizontal and upright surfaces thereby to clean the surfaces. In a particular use of the apparatus it may be utilised for automatically cleaning the floor and walls of a swimming pool.
According to the invention there is provided an apparatus for cleaning a surface submerged in a liquid, the apparatus including
A body adapted to be automatically displaced across the surface; and PA1 A main buoyancy member displaceably attached to the body so as to be automatically displaceable relative to the body by the buoyant forces which it, in use, experiences, in accordance with the attitude assumed by the body.
Conveniently, the buoyancy member may be pivotally attached to the body. For example, the buoyancy member may be attached to one end of a lever arm, the other end of which is pivotally attached to the body. Thus, the buoyancy member may be constrained to move in an arcuate manner laterally with respect to the body.
The buoyancy member may be restricted to be displaceable on only one side of the body. Alternatively, it may be free to move from one side of the body to the other.
The buoyancy member may follow a path that is suitably located with respect to the centre of gravity of the body. Further, the position or positions at which the buoyancy member exerts a buoyant force on the body may be suitably determined with reference to the centre of gravity of the body.
In a preferred emodiment, the body may have a head portion engageable with the surface to be cleaned, the lever arm being attached to the body towards the head portion thereof. Further, the pivotal axis may be horizontally disposed when the head portion is engaged with a horizontally disposed surface. Thus, when the head portion is engaged with the horizontally disposed surface, the main buoyancy member will pivot the lever arm such that the main buoyancy member is vertically disposed above the pivotal axis. When the apparatus moves onto a wall portion, such that the head portion is then engaged with a vertically or uprightly disposed surface, with the body extending upwardly from the head portion, the main buoyancy member will pivot towards the body portion. Then, if the body portion is canted over a predetermined extent, the buoyant force which the main buoyancy member experiences will cause it to pivot away from the body towards the head portion, exerting a force on the body which tends to lift the head portion, thereby displacing the effective centre of gravity of the apparatus away from the head portion.
The apparatus may be adapted such that the pivotal axis of the main buoyancy member is tiltable about a tilting axis relative to the body, the apparatus being provided with a tilting means for automatically varying the orientation of the pivotal axis relative to the body in accordance with the attitude assumed by the body. Preferably, the tilting axis is perpendicular to the pivotal axis.
As a preferred embodiment, the tilting means may comprise a tilting buoyancy member attached to the main buoyancy member so as to cause the pivotal axis to be tilted in accordance with the attitude assumed by the body. In order to minimise the extent to which the body must be canted over before the main buoyancy member pivots, the tilting buoyancy member may be adapted to tilt the pivotal axis out of a vertical plane when the head portion is engaged with a vertically disposed surface and the body is canted over to a predetermined extent.
Further, the tilting buoyancy member may be pivotally secured to the body, the lever arm then being pivotally fast with the tilting buoyancy member.
In an alternative form, the main buoyancy member could be attached to a cranked level arm, the crank in the level arm then constituting the tilting means.
According to a further aspect of the invention, there is provided a flange for an apparatus for cleaning a surface submerged in a liquid, the flange being attachable to the apparatus about a mouth portion thereof which is engageable with the surface to be cleaned, and the perimetral region, at least, of the flange being resiliently extensible.
The flange may conveniently be in the form of a flexible, substantially planar disc having a central aperture. Further, the perimetral region may be corrugated or wrinkled such that it may be resiliently extended, to thereby increase its effective surface area. Thus, the flange may have a number of concertina-like folds. These folds may radiate outwardly from a central region of the flange.
The flange may be of a suitable synthetic plastics material and may be moulded in a suitable mould.
Further according to this aspect, the invention extends to an apparatus for cleaning a surface submerged in a liquid, which includes a flange as indicated above.
According to a third aspect of the invention, there is provided a cleaning head for an apparatus for cleaning a surface submerged in a liquid, the cleaning head having a region engageable with the surface, which region has a plurality of zones having differing frictional characteristics.
By this means, the cleaning apparatus may operate effectively on a number of different surfaces, such as a metal surface, a concrete surface, a painted surface, a surface lined with a synthetic plastics material, or the like.
The zones may be provided with differing frictional characteristics either by providing the zones with different surface textures, or by forming them from different materials.
Still further, the invention extends to a cleaning head for an apparatus for cleaning a surface submerged in a liquid, the cleaning head having attachment means whereby surface engaging members, which engage, in use, the surface to be cleaned, may be attached to the cleaning head.
More particularly, the attachment means may comprise a plurality of sockets in which the surface engaging members are received. In this case, the surface engaging members may be in the form of studs or inserts which are insertable in the sockets. Such studs or inserts may be secured to the cleaning head in any suitable manner, for example frictionally or adhesively.
Finally, the invention extends to an apparatus for cleaning a surface submerged in a liquid, which includes a cleaning head in accordance with the invention.